383 or 408 Street Car??
10-06-2013, 09:35 PM
#1
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383 or 408 Street Car?? Everything that I have been finding is that the HP and the street ability with a LS1 383 and an LQ9/LS2 408 are the same.
What is really the difference besides the cubes is bigger then the other??
I don't want to put any FI on the motor. What way should I go??
What is really the difference besides the cubes is bigger then the other??
I don't want to put any FI on the motor. What way should I go??
10-07-2013, 07:46 AM
#2
Everything that I have been finding is that the HP and the street ability with a LS1 383 and an LQ9/LS2 408 are the same.
You can make either perfectly driveable or a pain in the *** to drive. It's not necessarily the cubes that determine that, it's other things like the cam, heads etc.
10-07-2013, 09:20 AM
#4
Unless you have heads that can take advantage of the 4" bore of the 408 you're not going to gain much. With all else being equal, you can put a little more cam in a 408 for a little more power and maintain the same streetability.
Since both have a 4" stroke, torque output is pretty close actually. You can expect 450-480 in a well sorted 383 and 470-510 in a 408. HP would be a function of those torque numbers x RPM. So expect 470-520rwhp out of a well-sorted 383 and 490-550rwhp out of the 408 (with the top of those numbers requiring some big cams/high-flowing heads).
The 408 is a 100lbs weight penalty and may cost more if you plan on reusing your LS1 block vs sourcing a 6L block.
Since both have a 4" stroke, torque output is pretty close actually. You can expect 450-480 in a well sorted 383 and 470-510 in a 408. HP would be a function of those torque numbers x RPM. So expect 470-520rwhp out of a well-sorted 383 and 490-550rwhp out of the 408 (with the top of those numbers requiring some big cams/high-flowing heads).
The 408 is a 100lbs weight penalty and may cost more if you plan on reusing your LS1 block vs sourcing a 6L block.
10-07-2013, 08:39 PM
#7
Unless you have heads that can take advantage of the 4" bore of the 408 you're not going to gain much. With all else being equal, you can put a little more cam in a 408 for a little more power and maintain the same streetability.
Since both have a 4" stroke, torque output is pretty close actually. You can expect 450-480 in a well sorted 383 and 470-510 in a 408. HP would be a function of those torque numbers x RPM. So expect 470-520rwhp out of a well-sorted 383 and 490-550rwhp out of the 408 (with the top of those numbers requiring some big cams/high-flowing heads).
The 408 is a 100lbs weight penalty and may cost more if you plan on reusing your LS1 block vs sourcing a 6L block.
Since both have a 4" stroke, torque output is pretty close actually. You can expect 450-480 in a well sorted 383 and 470-510 in a 408. HP would be a function of those torque numbers x RPM. So expect 470-520rwhp out of a well-sorted 383 and 490-550rwhp out of the 408 (with the top of those numbers requiring some big cams/high-flowing heads).
The 408 is a 100lbs weight penalty and may cost more if you plan on reusing your LS1 block vs sourcing a 6L block.
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10-08-2013, 02:14 PM
#8
You can optimize for the 4" bore though and pickup more than 5-7cfm. 5-7cfm across the board is noticeable, especially when coupled with a larger cam. That'll make more power.
My point was, however, you're not looking at some giant discrepancy.
If you really want to push power, look for the 4.125" bore motors... 427+ as then you can run big cathedral heads or LS7 heads and make serious power.
My point was, however, you're not looking at some giant discrepancy.
If you really want to push power, look for the 4.125" bore motors... 427+ as then you can run big cathedral heads or LS7 heads and make serious power.
